(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2003/0025401 A1
`(43) Pub. Date:
`Feb. 6, 2003
`Popescu-Stanesti et al.
`
`US 20030025401A1
`
`(54) INTELLIGENT ADAPTER
`
`Publication Classi?cation
`
`(76) Inventors: Vlad Popescu-Stanesti, San Jose, CA
`(US); Constantin Bucur, Santa Clara,
`CA (US)
`
`Correspondence Address:
`Grossman, Tucker, Perreault & P?eger, PLLC
`795 Elm Street, Suite 604
`Manchester, NH 03101 (US)
`
`(21) Appl. No.:
`
`10/055,810
`
`(22) Filed:
`
`Jan. 23, 2002
`
`Related US. Application Data
`
`(60) Provisional application No. 60/309,459, ?led on Aug.
`1, 2001.
`
`(51) Int. Cl? ...................................................... .. H02J 1/00
`(52) US. Cl. ............................................................ ..307/149
`
`(57)
`
`ABSTRACT
`
`In one aspect the present invention provides an AC/DC or
`DC/DC adapter, comprising circuitry to generate a signal
`proportional to the maximum adapter current. In another
`aspect, the present invention provides a portable electronic
`device, comprising circuitry to receive a signal proportional
`to the maximum current supplied to the portable electronic
`device and a charger controller. Still another aspect of the
`present invention provides an adapter topology system,
`comprising an AC/DC or DC/DC adapter comprising cir
`cuitry to generate a signal proportional to the maximum
`adapter current; and a portable electronic device adapted to
`receive poWer from said adapter and to receive said signal
`proportional to the maximum adapter current.
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`Apple 1016 - Page 1
`
`

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`Patent Application Publication
`
`Feb. 6, 2003 Sheet 1 0f 4
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`US 2003/0025401 A1
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`Apple 1016 - Page 2
`
`

`
`Patent Application Publication
`
`Feb. 6, 2003 Sheet 2 0f 4
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`US 2003/0025401 A1
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`Apple 1016 - Page 3
`
`

`
`Patent Application Publication
`
`Feb. 6, 2003 Sheet 3 0f 4
`
`US 2003/0025401 A1
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`Apple 1016 - Page 4
`
`

`
`Patent Application Publication
`
`Feb. 6, 2003 Sheet 4 0f 4
`
`US 2003/0025401 A1
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`Apple 1016 - Page 5
`
`

`
`US 2003/0025401 A1
`
`Feb. 6, 2003
`
`INTELLIGENT ADAPTER
`
`[0001] The present invention claims bene?t under 35 USC
`§ 119(e) of US. provisional application Serial No. 60/309,
`459, ?led Aug. 1, 2001, and assigned to the same assignee.
`
`BACKGROUND OF THE INVENTION
`
`[0002] 1. Field of the Invention
`[0003] The present invention relates to adapter topologies,
`and more particularly, to adapter topologies that generate
`information related to available or maximum adapter current
`and to electronic devices con?gured to receive this infor
`mation. Particular utility for the present invention is in
`portable electronic devices, hoWever, the present invention
`is equally applicable to any device that uses an adapter to
`derive poWer.
`
`[0004] 2. Description of Related Art
`[0005] Most portable electronic devices (e.g., portable
`computers, cell phones, PDAs, etc.) in use today utiliZe an
`AC/DC or DC/DC adapter that can be plugged into a Wall
`outlet or cigarette lighter, etc., used to poWer the device, and
`possibly charge the batteries simultaneously. A typical
`adapter simply supplies poWer, and provides no information
`to the charger circuit as to the maximum available poWer
`that can be delivered by the adapter. To control the poWer
`delivered to the batteries (for charging) and to the device, a
`charger circuit is provided Which regulates the How of
`current from the adapter. An example of charger topologies
`are provided in US. Pat. Nos. 6,246,215 and 6,329,796; and
`US. patent application Ser. No. 09/948,828, titled “Voltage
`Mode High Accuracy Battery Charger”, all assigned to
`O2Micro International Limited, and incorporated by refer
`ence herein in their entirety. Such charger topologies
`dynamically allocate available adapter current betWeen the
`batteries and the device.
`
`[0006] FIG. 1 depicts a conventional topology that
`includes an adapter 1 and mobile equipment 2. The terms
`“mobile equipment” or “portable electronic device” as used
`herein mean a portable computer, cell phone, PDA, and/or
`any other device that uses an adapter to derive poWer. The
`adapter 1 generates a signal 90 indicative of the type of
`adapter used. This signal only has tWo states, and is used as
`an identi?cation (ID) signal that represents the type of
`adapter used. The adapter 1 of FIG. 1 can be of tWo types:
`a high poWer adapter (e.g., 70W) or a loW poWer adapter
`(e.g., 45W). The high poWer type of adapter generates no
`signal 90, While the loW poWer adapter generates a signal 90
`having a predetermined value. The mobile equipment is
`adapted With a sWitch 4, Whose conduction state determines
`the type of adapter (loW poWer or high poWer) present.
`Assuming that high poWer adapter is present, sWitch 4 is
`OFF. If a loW poWer adapter is present, signal 90 turns
`sWitch 4 ON. Signal 90 is a signal representing the type of
`adapter present (loW or high), and may be used by poWer
`management processors or charger circuits. Note that this
`topology only has tWo states representing the presence of a
`loW poWer adapter or high poWer adapter, and thus cannot
`generate information related to the maximum or available
`poWer provided by the adapter. Note also that this topology
`requires that the adapter and mobile equipment be matched,
`such that the adapter could not be used With other mobile
`equipment and vice-versa.
`
`[0007] Thus, there exists a need to provide an adapter
`topology that provides information related to maximum
`adapter current, Which may be utiliZed by a charger to
`accurately allocate available current to batteries (for charg
`ing) and a device (for operation). There also exists a need for
`an adapter topology that permits the adapter to be used With
`a Wide range of devices so that the adapter is can be used
`With many types of mobile equipment devices.
`
`SUMMARY OF THE INVENTION
`
`[0008] Accordingly, in one aspect the present invention
`provides an AC/DC or DC/DC adapter, comprising circuitry
`to generate a signal proportional to the maximum adapter
`current.
`
`[0009] In another aspect, the present invention provides a
`portable electronic device, comprising circuitry to receive a
`signal proportional to the maximum current supplied to said
`portable electronic device and a charger controller.
`
`[0010] Still another aspect of the present invention pro
`vides an adapter topology system, comprising an AC/DC or
`DC/DC adapter comprising circuitry to generate a signal
`proportional to the maximum adapter current; and a portable
`electronic device adapted to receive poWer from said adapter
`and to receive said signal proportional to the maximum
`adapter current.
`
`[0011] It Will be appreciated by those skilled in the art that
`although the folloWing Detailed Description Will proceed
`With reference being made to preferred embodiments and
`methods of use, the present invention is not intended to be
`limited to these preferred embodiments and methods of use.
`Rather, the present invention is of broad scope and is
`intended to be limited as only set forth in the accompanying
`claims.
`
`[0012] Other features and advantages of the present inven
`tion Will become apparent as the folloWing Detailed
`Description proceeds, and upon reference to the DraWings,
`Wherein like numerals depict like parts, and Wherein:
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`[0013]
`FIG. 1 depicts a conventional adapter topology;
`[0014] FIG. 2 depicts one exemplary adapter topology
`system of the present invention;
`[0015] FIG. 3 depicts another exemplary adapter topology
`system of the present invention;
`[0016] FIG. 4 depicts another exemplary adapter topology
`system of the present invention;
`[0017] FIG. 5 depicts another exemplary adapter topology
`system of the present invention;
`[0018] FIG. 6 depicts another exemplary adapter topology
`system of the present invention; and
`[0019] FIG. 7 depicts another exemplary adapter topology
`system of the present invention.
`
`DETAILED DESCRIPTION OF THE
`EXEMPLARY EMBODIMENTS
`
`[0020] As a broad overvieW, the adapter topology system
`embodiments of FIGS. 2-7 generate an identi?cation signal
`(ID) proportional to the maximum or available adapter
`
`Apple 1016 - Page 6
`
`

`
`US 2003/0025401 A1
`
`Feb. 6, 2003
`
`current. Also, the topologies disclose electronic device con
`?gured to receive the signal proportional to the maximum or
`available adapter current. The system comprises both the
`adapter and the portable device, but the present invention is
`also directed to the adapter and the portable device inde
`pendent of each other. A battery charger controller, associ
`ated With the portable electronic device (and such as pro
`vided in the aforementioned US. Patents) may be adapted to
`utiliZe this signal to dynamically allocate poWer betWeen the
`batteries (for charging) and the mobile equipment (for
`operating poWer). Such battery charger controllers generally
`operate to give the mobile equipment poWer, and Will use
`any remaining current to charge the batteries. The present
`invention is not limited to a particular charger controller, and
`a charge controller is not necessary for an understanding of
`the present invention.
`[0021] FIG. 2 depicts one exemplary adapter topology
`system 100 of the present invention. In this embodiment, the
`adapter 5 includes an embedded current limit encoder 6 that
`generates a signal 50 indicative of the maximum current
`provided by the adapter 5. The encoder 6 may comprise, for
`example, serial code generating circuitry, current-to-fre
`quency coding circuitry and/or other coding circuitry knoWn
`in the art. Of course, the adapter supplies poWer to the device
`7 (via the +/—poWer lines), as Well as signal 50. The mobile
`equipment 7 is adapted With current limit decoding circuitry
`8 that decodes signal 50. The decoding circuitry 8 is
`appropriately matched to the coding circuitry 6 to code and
`decode signal 50. The decoding circuitry 8 generates a
`voltage signal 16 (VID) that is proportional to the adapter
`current limit I ADilim, i.e., VID=k><IADiHnT Note that in this
`exemplary embodiment, the voltage signal 16 can represent
`changes in the adapter current. In other Words, signal 16
`changes With changes in the adapter current limit. In this
`example, signal 16 changes linearly, hoWever the present
`invention equally contemplates a nonlinear relationship
`betWeen the maximum adapter current signal and signal 16.
`Signal 16 is sent to a charger circuit (or other poWer
`management device) that can adjust poWer delivered to both
`batteries and the device based on the value of signal 16.
`[0022] FIG. 3 depicts another exemplary adapter topology
`system 110 of the present invention. In this exemplary
`embodiment, the adapter 9 includes a current sense encoder
`10 that generates a digital coded signal 54 indicative of the
`maximum current limit of the adapter 9. The coded signal 54
`is sent (via a conventional and/or proprietary digital chan
`nel) to a keyboard controller 12 (or any other type of
`microcontroller) associated With the mobile device. The
`keyboard controller 12 is a conventional device found in
`portable computers, and may be appropriately adapted to
`generate an SMBus serial communications signal 56 (des
`ignated as SMBus_Clk and SMBus_Data 56 in the Figure).
`Signal 56 is an SMBus digital signal representing the
`maximum current limit of the adapter 9.
`
`[0023] The charger circuit 15 is of the type that can be
`externally programmed With a signal indicative of the maxi
`mum current limit. Charger 15 includes an SMBus converter
`13 that essentially comprises a DAC circuit to convert
`digital signal 56 into an analog signal 58. A sense compara
`tor 14 generates a signal indicative of the total current
`delivered by the adapter (across sense resistor Rsense) and
`generates a measured adapter current value Imeas. Imeas
`and signal 58 are compared in comparator 16 that generates
`
`a signal indicative of the difference betWeen the maximum
`available adapter current (signal 58) and the measured
`current supplied by the adapter. This value is used by other
`components in the charger (not shoWn and not necessary for
`an understanding of the present invention, but fully dis
`closed in the aforementioned patents) to dynamically allo
`cate poWer delivered to the batteries and the mobile equip
`ment.
`[0024] FIG. 4 depicts another exemplary adapter topology
`system 120 of the present invention. In this embodiment, the
`adapter 17 includes an embedded identi?cation resistor RID
`18 that is connected in series With the adapter voltage (+)
`and the mobile device. RID is ?xed for a given adapter, and
`generates a ?xed voltage drop. The mobile equipment 19
`includes a reference resistor Rref 20 connected to the iden
`ti?cation resistor and to ground
`RID and Rref, taken
`together, comprise a voltage divider, and it folloWs that VID
`is based on RID, Rref, and the adapter voltage. The adapter
`voltage, VID, across the reference resistor represents the
`adapter current capability, With a scale factor as a function
`of the value of the sense resistor Rsense, Rref and the charger
`current gain
`If portability of the adapter 17 is desirable,
`this scale factor may be standardiZed by providing a stan
`dardiZed value for Rref. As With the previous embodiments,
`VID may be utiliZed by the charger circuitry to dynamically
`allocate poWer available from the adapter 17 based on the
`knoWn value of the maximum or available poWer available.
`[0025] FIG. 5 depicts another exemplary adapter topology
`system 130 of the present invention. Topology 130 is similar
`to topology 120 of FIG. 4, except the identi?cation voltage,
`VID, is independent of the adapter voltage. This embodiment
`also depicts some details of the charger circuitry 25
`(although not necessary for an understanding of the present
`invention). In this embodiment, the adapter 21 includes an
`embedded identi?cation resistor RID connected to the
`adapter ground and to the mobile equipment 23 (via, for
`example, the poWer cord (+/—) of the adapter). The mobile
`equipment includes an embedded pull-up resistor Rref 24
`that is coupled betWeen signal line 62 and a regulated loW
`voltage source LV (e.g., 5V, 3.3V, etc.), thus forming a
`voltage divider de?ned by RID and Rref. Identi?cation signal
`62, then, is a proportional voltage signal VID=k><IAILlirn
`indicative of the maximum or available adapter current;
`Where I ADilim is the adapter current limit and k is a propor
`tionality constant. Note that VID depends only on RID and
`Rref, and is independent of the adapter voltage.
`[0026] FIG. 5 also provides more detailed structure of an
`exemplary charger controller 25. The charger 25 includes a
`current sense ampli?er 28 and an error ampli?er 26. The
`current sense ampli?er generates a signal (I Acimeas) indica
`tive of the actual adapter current generated across the current
`sense resistor Rsense 27. Error ampli?er compares I Acmeas
`With VID (the voltage signal representing the maximum
`available adapter current) to generate a control signal used
`by the poWer regulating feedback loop of the charger con
`troller 25. Again, the details of the charger controller are not
`necessary for an understanding of the present invention, and
`are being provided herein only as an example of hoW one
`skilled in the art may utiliZe the maximum current signal.
`Accordingly, the present invention is not limited to the
`exemplary charger controller circuitry described herein.
`[0027] FIG. 6 depicts another exemplary adapter topology
`system 140. This embodiment generates a normaliZed
`
`Apple 1016 - Page 7
`
`

`
`US 2003/0025401 A1
`
`Feb. 6, 2003
`
`adapter current signal. This embodiment also depicts some
`elements of the charger controller circuit. In this embodi
`ment, the adapter 29 includes an embedded current sense
`resistor (Rsense) 30 and a current sense ampli?er 31. These
`components might typically be associated With a charger
`controller. The ampli?er 31 provides a normaliZed current
`signal 64 that is proportional to the adapter current (I AD><s).
`The gain of the ampli?er 31 is selected to provide a
`standardiZed output When the adapter reaches its maximum
`current level. In other Words, ampli?er 31 has a set upper
`gain. The normaliZed current signal 64 is a value indicative
`of a percentage of maximum current.
`
`[0028] The mobile equipment 32 in this embodiment
`includes an embedded resistor 33 Rsys coupled betWeen the
`normaliZed current signal 64 and ground. Embedding Rsys
`in this manner eliminates error generated by the parasitic
`voltage drop of the adapter. The voltage drop across Rsys is
`indicative of the percentage of maximum current of the
`adapter, and is expressed as VIAD=Rsys><IAD><s More pre
`cisely, the voltage VIAD represents the actual adapter current
`as a percentage of the rated adapter current. Error ampli?er
`compares this value to a value indicative of 100% of the
`adapter current (VIADiHm) and generates a control signal
`used by the poWer regulation feedback loop of the charger
`controller.
`
`[0029] FIG. 7 depicts yet another exemplary adapter
`topology system 150. This embodiment is similar to the
`topology of FIG. 3, except that the DAC 13 is replaced With
`an SMBus programmable interface 36 and a multiplexed
`DAC 37. The DAC 37 receives the output of the SMBus
`interface 36 and generates a plurality of programmable
`analog signals used by the charger controller 15, as Will be
`understood in the art. Examples of such programmable
`signals include the charging current reference IDAC 38, the
`charging voltage reference VDAC 39 and the adapter current
`limit IACLIM.
`
`[0030] The current limit encoder 10 embedded in the
`adapter 9 sends data representing the adapter maximum
`current to the keyboard controller (KBC) 12 (or any other
`microcontroller) in the mobile equipment 11. The KBC 12
`issues appropriate SMBus commands representing the
`adapter current limit, the battery charging voltage IDAC and
`the battery charging current VDAC to the charger 15 via
`SMBus communication protocols. The charger 15 uses the
`SMBus programmable interface 36 to decode the SMBus
`commands. The decoded values are sent to the multiplexed
`DAC 37, one by one, and are converted to analog signals on
`the different outputs 38, 39 and 40. The signals (voltages)
`are used as reference signals for error ampli?ers Within the
`charger, such as error ampli?er 16 depicted.
`
`[0031] In all of the embodiments described herein the
`identi?cation signal generated by the adapter represents a
`dynamic indication of the maximum available poWer for the
`particular adapter, and can change linearly With changes in
`available adapter current (power). Although the draWings
`generally depict a separate signal line betWeen the adapter
`and the mobile equipment, those skilled in the art Will
`recogniZe that numerous other communication methodolo
`gies could be employed to communicate information
`betWeen the adapter and the mobile equipment. For
`example, the embodiments of FIGS. 2, 3 and 7 may be
`adapted to include Wireless communication (e.g., RF, IR,
`
`etc) betWeen the adapter and the mobile equipment to
`communicate maximum or available adapter current infor
`mation from the adapter to the mobile equipment. LikeWise,
`FIG. 6 could be similarly modi?ed and further modi?ed
`With a programmable current source (not shoWn) embedded
`in the mobile equipment. This programmable current source
`could be coupled to Rsys and programmed to generate the
`proportional adapter current value (IADxs). Alternatively,
`such information could be communicated over the existing
`poWer lines (+ and/or —) using modulation/demodulation
`techniques knoWn in the art to communicate available poWer
`data over the existing poWer lines.
`
`[0032] Further modi?cations Will become apparent to
`those skilled in the art, and all such modi?cations are
`deemed Within the spirit and scope of the present invention
`as de?ned by the appended claims.
`
`1. An AC/DC or DC/DC adapter, comprising circuitry to
`generate a signal proportional to the maximum adapter
`current.
`2. An AC/DC or DC/DC adapter as claimed in claim 1,
`said circuitry comprising a current limit encoder generating
`said signal proportional to the maximum adapter current.
`3. An AC/DC or DC/DC adapter as claimed in claim 1,
`said circuitry comprising an identi?cation resistor coupled to
`the positive adapter voltage.
`4. An AC/DC or DC/DC adapter as claimed in claim 1,
`said circuitry comprising an identi?cation resistor coupled to
`the negative adapter voltage.
`5. An AC/DC or DC/DC adapter as claimed in claim 1,
`said circuitry comprising a current sense resistor coupled to
`the positive adapter voltage and a current sense comparator
`coupled to said current sense resistor, said current sense
`comparator having a set upper gain and generating a nor
`maliZed value of said signal proportional to the maximum
`adapter current.
`6. An adapter topology system, comprising
`
`an AC/DC or DC/DC adapter comprising circuitry to
`generate a signal proportional to the maximum adapter
`current; and
`
`a portable electronic device adapted to receive poWer
`from said adapter and to receive said signal propor
`tional to the maximum adapter current.
`7. An adapter topology system as claimed in claim 6, said
`circuitry comprising a current limit encoder generating said
`signal proportional to the maximum adapter current; said
`portable electronic device comprising a current limit
`decoder receiving said signal proportional to the maximum
`adapter current and generating a voltage proportional to the
`rated current of said adapter.
`8. An adapter topology system as claimed in claim 6, said
`current limit decoder comprising a keyboard controller, said
`keyboard controller generating SMBus commands to a digi
`tal to analog circuit to generate said voltage proportional to
`the rated current of said adapter.
`9. An adapter topology system as claimed in claim 6, said
`circuitry comprising an identi?cation resistor coupled to the
`positive adapter voltage; said portable electronic device
`comprising a reference resistor coupled betWeen said iden
`ti?cation resistor and ground thereby forming a voltage
`divider generating said voltage proportional to the rated
`current of said adapter.
`
`Apple 1016 - Page 8
`
`

`
`US 2003/0025401 A1
`
`Feb. 6, 2003
`
`10. An adapter topology system as claimed in claim 6,
`said circuitry comprising an identi?cation resistor coupled to
`the negative adapter voltage; said portable electronic device
`comprising a reference resistor coupled betWeen said iden
`ti?cation resistor and a reference voltage thereby forming a
`voltage divider generating said voltage proportional to the
`rated current of said adapter.
`11. An adapter topology system as claimed in claim 6, said
`circuitry comprising a current sense resistor coupled to the
`positive adapter voltage and a current sense comparator
`coupled to said current sense resistor, said current sense
`comparator having a set upper gain and generating a nor
`maliZed value of said signal proportional to the maximum
`adapter current; said portable electronic device comprising a
`resistor coupled betWeen said signal proportional to the
`maximum adapter current and ground thereby generating a
`voltage representing the percentage that the actual current is
`With respect to the maximum current.
`12. An adapter topology system as claimed in claim 6,
`said current limit decoder comprising a keyboard controller,
`said keyboard controller generating SMBus commands to a
`multiplexed digital to analog converter through an SMBus
`programmable interface, said multiplexed digital to analog
`converter generating said signal proportional to the maxi
`mum adapter current.
`13. A portable electronic device, comprising circuitry to
`receive a signal proportional to the maximum current sup
`plied to said portable electronic device and a charger con
`troller.
`14. A portable electronic device as claimed in claim 13,
`said circuitry comprising a current limit decoder receiving a
`coded signal indicative of said signal proportional to the
`maximum current supplied to said portable electronic device
`and generating a voltage proportional to the rated current of
`an AC/DC or DC/DC adapter supplying poWer to said
`portable electronic device.
`
`15. A portable electronic device as claimed in claim 14,
`said current limit decoder comprising a keyboard controller,
`said keyboard controller generating SMBus commands to a
`digital to analog circuit to generate said voltage proportional
`to the rated current of said adapter.
`16. A portable electronic device as claimed in claim 13,
`said circuitry comprising a reference resistor coupled
`betWeen said signal proportional to the maximum adapter
`current and ground generating said voltage proportional to
`the rated current of an AC/DC or DC/DC adapter supplying
`poWer to said portable electronic device.
`17. A portable electronic device as claimed in claim 13,
`said circuitry comprising a reference resistor coupled
`betWeen said signal proportional to the maximum current
`supplied to said portable electronic device and a reference
`voltage, and generating a voltage proportional to the rated
`current of an AC/DC or DC/DC adapter supplying poWer to
`said portable electronic device.
`18. A portable electronic device as claimed in claim 13,
`said signal proportional to the maximum current supplied to
`said portable electronic comprising normaliZed signal; said
`circuitry comprising a resistor coupled betWeen said nor
`maliZed signal and ground thereby generating a voltage
`representing the percentage that the actual current supplied
`to said portable electronic device is With respect to the
`maximum current.
`19. A portable electronic device as claimed in claim 14,
`said current limit decoder comprising a keyboard controller,
`said keyboard controller generating SMBus commands to a
`multiplexed digital to analog converter through an SMBus
`programmable interface, said multiplexed digital to analog
`converter generating said signal proportional to the maxi
`mum current supplied to said portable electronic device.
`
`Apple 1016 - Page 9